Telescopic drill rods for soil drilling equipments



June 30, 1970 A. KEHRBERGER 5 7 TELESCOPIC DRILL RODS FOR SOIL DRILLING EQUIPMENTS Filed March 14, 1969 ACHI KE BERGER 'By: {math- ATTORNE ys United States Patent O 3,517,760 TELESCOPIC DRILL RODS FOR SOIL DRILLING EQUIPMENTS Achim Kehrberger, Nellingen, Germany, assignor to Delmag-Maschinenfabrik Reinhold Dornfelrl, Esslingen,

Germany, a corporation of Germany Filed Mar. 14, 1969, Ser. No. 807,305

Claims priority, application Germany, Mar. 22, 1968, 1,287,534 Int. Cl. E21b 17/00 U.S. Cl. 175-321 7 Claims ABSTRACT OF THE DISCLOSURE A telescopic drill rod for a soil drilling equipment comprises an innermost drill rod member provided at its lower end with means for attaching a drill bit and at its upper end with a swivel for suspending the drill by a rope from the drilling equipment, a first telescopic tube surrounding the innermost drill rod member and at least a second telescopic tube surrounding the first telescopic tube, a -first damping means fastened to the lower end of the innermost drill rod member to provide a seating for the telescopic tubes, an end collar inside the lower end of the first telescopic tube, a second damping means demountably attached to the upper half of the innermost drill rod member and abutting when the drill rod is extended the end collar, and a third damping means attached to the other end of the first telescopic tube and abutting when the drill rod is extended a further end collar at the lower end of the second telescopic tube.

BACKGROUND OF THE INVENTION The present invention relates to drill rods for soil drilling equipments, and more particularly, to drill rods comprsing a number of members extendable in the manner of a telescope, in which an innermost drill rod member carries a drill at one end and is Suspended by means of a swivel at its other end from a drill lifting rope of the sol drilling equipment.

It is highly desrable, particularly for drilling equipments used in the construction of building foundations, that drill rods can be used for thecompletion of a bore without there being a need to assemble further members to the drill rod and thereby extend it during the actual drilling operation. It is therefore expedent to employ telescopically extendable drill rods. Such drill rods are operated with all members of the drill rod pushed together during the initial portion of a drilling operation, the drill suspension rope `then connecting at the innermost drill rod member. As the drilling operation progresses, the first and second and possibly also further telescopic tubes eX- tend downwards under gravity. Power transmission from the drilling table to the drill rod is effected via the outermost telescopic tube. V,

Conventional telescopic drill rods, so-called Kelley-rods, have an end collar in proximity to the upper end of the innermost drill rod member. The first telescopic tube, which has an end collar inside at the lower end, is pushed from below over this innermost drill rod member and, at the upper end, is screwed up to a flange, which in turn forms the stop for the second telescopic tube. The second telescopic tube in turn is provided with an end collar inside at the lower end and is pushed over the first telescopic tube from below in order to be screwed together a t the upper end with a flange which projects inwardly and outwardly to prevent on the one hand a gliding apart of the drill rod and to have on the other hand a support on the drilling table. This construction sulfers from the disadvantage, that the screw connections require additional labour during the drilling operation and is therefore costly. A further disadvantage is due to the stop members striking the flanges metallically during the running out of the telescopic tubes and thereby loosening connectng screws, which can then fall between the telescopic tubes to cause these to jam and require an expensive rep In a further known construction, the telescopic drill rod may be extended by hydraulc means. Although in this way the hard metallic strikes may be avoided, such a construction has the disadvantage that it is rather more complicated and consequently more expensive and less reliable.

It is an object of this invention to provide a telescopic drill rod which avoids or at least mitigates the disadvantages of prior drill rods referred to.

SUMMARY OF THE INVENTION According to one aspect of the invention, there is pro- Vided a telescopically extendable drill rod for soil drilling equipments, comprsing an innermost drill rod member provided at its lower end with means for attaching a drill bit and at its upper end With a swivel for suspend ing the drill by a rope from the drilling equipment, a first telescopic tube surrounding the innermost drill rod member and at least a second telescopic tube surrounding the first telescopic tube, a first damping means fas tened to the lower end of the innermost drill rod member to provide a seating for the telescopic tubes, an end collar inside the lower end of the first telescopic tube, a second damping means demountably attached to the upper half of the innermost drill rod member and abutting when the drill rod is extended the end collar, and a third damping means attached to the other end of the first telescopic tube and abutting when the drill rod is extending a further end collar at the lower end of the second telescopic tube.

i According to another aspect of the invention, there is provided a telescopically extendable drill rod for soil drilling equipments, comprsing an innermost drill rod member provided at its lower end with means for attaching a drill bit and at its upper end with a swivel for suspending the drill by a rope from the drilling equipment, a first telescopic tube surrounding the innermost drill rod member and at least a second telescopic tube surroundingthe first telescopic tube, a first damping means tastened to the lower end of the innermost drill rod member to provide a seating for the telescopic tubes, an end collar inside the lower end of the first telescopic tube, a second damping means demountably attached to the other end of the innermost drill rod member and abutting when the drill rod is extended the end collar, and a third damping;

means attached to the lower end of the second telescopic tube and abutting when the drill rod is extended a further end collar at the upper end of the first telescopic tube.

In the preferred cmbodiment, the drill rod comprises an annular projection supporting the first damping means at the lower end of the innermost drill rod member.. Expediently one or more of the damping means may be provided with a -radial slit. Preterably, the second damping means is fastened to the innermost drill rod member by a bolt coupled to the swivel.

The telescopic tubes may be of cylindrical cross-section and at least one of the damping means may be then in the shape of a ring.

BRIEF DESCRIPTION OF THE DRAWINGS Two embodiments of the invention will now be described by way of example with reference to the accompanying drawings, in which:

FIG. 1 shows a sectional view of a drill rod embodying the invention;

FIG. 2 shows a sectionai view on the line II-II in FIG.

FIG. 3 shows the drill rod in its fully extended condi tion; and

- FIG. 4 illustrates a further embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIGS. 1, 2 and 3 of the drawings, a drill rod 20 comprises an innermost drill rod member 1, which carries at its lower end 2 a drill 3 and at its upper end 4 a swivel 5, which is fastened by a bolt 6, which also provide means for demountably attaching a damping ring 7 to the upper end of the innermost drill rod member. The damping ring 7 additionally serves to prevent the sliding apart of the drill rod 20.

A damping ring 9 inserted in a plate 10 rests loosely on -a ring 8, which is welded to the drill rod member 1. A first telescopic tube 11 and a second telescopic tube 12 are carried by the plate 10. Welded to each of the telescopic tubes 11 and 12 are two dog ridges 13 on the outside and guiding segments 14 and 15 inside the lower end. The guiding segments 14 and 15 also serve as stop members. An end collar 16 is welded to the first telescopic tube 11 at its upper end. A damping ring 17 is located adjacent to the end collar 16. In the extended condition of the drill rod, as shown in FIG. 3, the damping ring 17 strikes the guide segment 15 of the second telescopic tube 12.

The drill rod 20 hangs by a flange 18 welded onto the second telescopic tube 12 in a schematically represented drilling table 19, which in turn is fastened `by supports 22 in a not shown guide slide.

When the drill rod is in its extended condition as shown in FIG. 3, the damping ring 7 rests on the guide segments 14 and the damping ring 17 rests on the guide segments 15. It can be seen from FIG. 3, that the damping ring 17 could be fastened on the guide segments 15 instead of being fastened or adjacent to, as hereinbefore described, the end collar 16. The drill rope 21 runs through the telescopic tubes 11 and 12 to the swivel at the end of the innermost drill rod member 1.

v FIG. 4 illustrates an alternative embodiment, in which rectangular tubes are employed instead of the round tubes described with reference to FIGS. 1 to 3. The reference numerals used in FIG. 4 correspond to those use for like members of the drill rod in FIGS. 1 to 3 and ditfer by the additon of a dash. Dog ridges 13 shown in FIG. 3 may be obviated by this Construction.

When assembling a drill rod embodying the invention, the first telescopic tube 11 with its guide segments 14, end collar 16 and damping ring 17 is lowered into the second telescopic tube 12 with its flange 18 and guide segments 15; the innermost drill rod member 1 is then pushed in from underneath with a loosely resting damping ring 9 and plate finally, the damping ring is fastened by the bolt 6. The damping ring 7 serves simultaneously as an end collar in order to prevent the sliding apart of the drill rod 20.

In a drilling operation, the drill rod 20 is initially used with all its members pushed together. As the drilling depth increases, the first telescopic tube 11 and the innermost dri11 rod member 1 extend downwards under gravity.

When required, soil may be removed from the drill 4 3 after pulling it out by the drill rope 21, which acts via the swivel 5 on the innermost drill rod member 1. When the drill 3 is thus lifted, the drill rod 20 retracts again telescopically. The telescopic tubes 11 and 12 rest on the plate 10, which together with the damping ring 9 mitigates the shock.

On reintroducing the drill 3 into the bore hole by slackening the drill rope 21, the single parts of the drill rod fall under gravity into the drill hole and strike very strongly upon each other in the respective end positions. These strikes are attenuated by the damping rings 7 and 17.

I claim:

1. A telescopic drill rod for a soil driiling equipment, comprising an innermost drill rod member, means for attachng a drill bit to said drill rod member, said attaching means being provided at one end of said drill rod member, a swivel for suspending the drill rod from said drilling equipment, said swivel being provided at the other end of said drill rod member, a first tube surrounding said drill rod member, a second tube surrounding said first tube, a first damping means provided at said one end of said drill rod member and arranged to provide a seating for said tubes, an end collor inside said first tube at its end adjacent said first damping means when the telescopic drill rod is in its collapsed state, a second damping means removably attached to said other end of said drill rod member and abutting said end collar when the drill rod is fully extended, a further end collar at one end of one of said tubes, and a third damping means attached to the op posite end of the other one of said tubes, said third damping means and said further end collar being arranged for abutting against each other when the drill rod is fully extended.

2. A drill rod as defined in claim 1, wherein said further end collar is inside and at the end of said second tube adjacent said first damping means when the telescopic drill rod is in its collapsed state, said third damping means being attached outside and at the opposite end of said first tube.

3. A drill rod as defined in claim 1, and further comprising an annular projection supporting said first damping means, said annular projection being provided on said drill rod member.

4. A drill rod as defined in claim 1, and further comprising a bolt releasably coupled to said swivel, said second damping means being attached to said drill rod member by said bolt.

5. A drill rod as defined in claim 1, wherein said tubes are of cylindrical cross-section.

6. A drill rod as defined in claim 5, wherein at least one of said damping means is in the shape of a ring.

7. A drill rod as defined in claim 1, wherein said tubes are of rectangular cross-section.

References Cited UNITED STATES PATENTS 656515 8/1900 Cassity et al -321 1,395,081 10/1921 Barry et al 175-321 X 2,066,794 1/ 1937 Miller 175-321 2,453,204 11/ 1948 Dobbs 175-321 3,292,976 12/1966 Leavell 173-139 JAMES A. LEPPINK, Primary Examiner 

